Voltage regulator system



Dec. 8, 1931. w. P. KoEcHEL VOLTAGE REGULATOR SYSTEM Filed June lO, 1929D o N -f /mm MMM/.7 K um mu M Mw Mv *i o l 4 V. z 3 2 M c o Y T l f u v.2 .n n e H w 6 .W4 1 m, f w. mw w. A

lNvENToR W. P. K orcHEl. BY/? 9 5%@ ATTORNE Patented Dec. 8, 1931 UNITEDSTATES PATENT OFFICE WALTER P. XOECHEL, 0F BLOOMFIEIID, `N'FT JERSEY,ASSIGOR T0 WESTINGHOUSE LAMP COMIPANY, A CORPORATION 0F PENNSYLVANIAVOLTAGE REGULATOR SYSTEM'.

Application filed June 10,

This invention relates to electrical systems and more particularlyrelates to electrical systems employing voltage regulator devices of thegaseous conduction type, and has for its object the provision of a meansof effecting the regulation of a fluctuating source of voltage to obtaintherefrom a substantially constant voltage.

- Another object of this invention is to provide a voltage regulatingsystem utilizing a plurality of glow regulator tubes, in which theelectrical load of the system is equally distributed between theregulator tubes.

Another object of this invention is to provide a system for operatinglow voltage electrical apparatus atta substantially constant potentialfrom a high voltage source of fluctuating potential.

Another object of this invention is to provide a voltage regulatingsystem employing a plurality of glow regulating tubes in which thedistribution of the electrical load between the tubes may be adj ustablyequalized.

Other objects and advantages will hereinafter appear.

In accordance with the objects of my invention I have found that in avoltage regulating system employing a plurality of gaseous conductionregulator devices of a type such as is disclosed in copendingapplication of Harvey C. Rentschler, Serial No. 158,503 filed January 3,1927, entitled Electron discharge device, which is assigned to the sameassignee as the present invention, it is essential for the successfuloperation of the system that means be provided for equally distributingthe electrical load of the system between the respective voltageregulating devices utilized therein.

Devices of the type disclosed in the above identified copendingapplication by Harvey C. Rentschler are comprised substantially of anenclosing glass envelope containing a cylindrical cathode of relativelylarge area, a centrally disposed anode of small area and a filling of aninert monatomic gas such as argon, at a pressure of about 5 to 6 m. m.of mercury. The anode consists at least in part of thorium and a gettermaterial such as misch metal is employed on the cathode for puri- 1929.Serial No. 369,906.

fying the gas filling and for lowering the starting and operatingpotentials of the tube.

One of the characteristics of such a tube is that it has a nearlyconstant voltage drop across its terminals when the current flowtherethrough varies over a considerable range, and this characteristichas been utilized for maintaining a constant voltage across theterminals of electrical apparatus conected in shunt relation to theregulator tu e.

It is found, however,.that the current carrying capacity of the deviceis limited by the size of the cathode and it is inexpedient from amanufacturing and commercial application standpoint to increase the sizeof the cathode beyond the point which provides a Current carryingcapacity in the tube 0f approximately 2.0 amperes.

In electrical systems employing such devices in which a current greaterthan the carrying capacity of a single tube is flowing, itis essentialthat a plurality of such devices be utilized in parallel to preventoverloading of a single tube.

The voltage drop of a voltage regulator tube of approximately 2 amperecurrent carrying capacity is designed to be approximately 100 volts.

It is found, however, that due to manufacturing Variables over whichthere is little control, the voltage regulator tubes individually varyfrom 95 to 105 volts in the voltage drop across the tubes. In connectingthese tubes in parallel in any given electrical system the tube havingthe lowest voltage drop will draw the major portion of the current andthus become overloaded. Additional voltage dissipating means musttherefore bel the source of positive potential actuating the regulatortube and ground potential and preferably lower than the operatingpotential of the said voltage regulator tube. By varying the setting ofthe potentiometer center tap the voltage drop across the tube may bevaried, and the current that may be drawn by the tube thus adjusted toany desired figure. By connecting a plurality of these tubes in asimilar manner, in parallel from a common source of positive potentialeach tube may thereby be adjusted to draw any desired current from thecircuit.

By applying a current of approximately constant voltage across thetubes, the individual current carryingcapacities of the tubes may beregulated and equalized by means of the variable adjustment on theindividual potentiometer.

Before further disclosing the nature of my invention reference should behad to the accompanying drawings wherein Fig. 1 represents a schematicdiagram of an electrical circuit embodying the features of my invention;and

Fig. 2 shows a side elevational view partly in cross section of avoltage regulator tube of the gaseous conduction type utilized in theelectrical circuit in Fig. 1.

In Fig. 1 is shown a 250 watt 64 volt headlight lamp (1) of thetypecommonly utilized on electric locomotives, vstreet cars and thevlike, connected across the line voltage C and D. The line voltage isliable to uctuate widely such as from a minimum of 300 volts to amaximum of 900 volts. Suitable dissipating resistances 5, 6 and 7 areinterposed in series with the lamp 1 across the terminals to reduce thevariable line voltage to the de. sired lamp voltage of approximately 64volts. It is desirable to protect the lamp from premature burnout bymeans of voltage regulator tubes 2, 3 and 4 of the gas discharge typehaving a voltage drop of approximately 100 `volts, which tubes areconnected in parallel with the incandescent lamp from a point (A) in thedissipating resistances 5 and 6 which gives approximately a 100 voltdrop to ground potential. Y

Interposed between the negative terminal and the voltage regulator tubesand electrically connected in'parallel are variable potentiometers 8, 9and 10 having one terminal of each connected to the negative or groundpotential and the other terminal connected back to a source of positive-potential on the negative side of the lamp. A dissipating resistance 7,of approximately an equal value to the variable resistance ofthepotentiorieters 8, .9 and 10 is interposed between the neg ativeterminal of the circuit and the lamp. The cathode of the voltageregulator tube is connected to the centertap of the potentiometers inthe manner indicated.

The glow discharge regulator tubes 2, 3 and '4 in addition to theregular anode 11, and cathode 12, have an auxiliary or startingelectrode 13 which is connected to a source of higher potential (B) tofacilitate the break down and operating characteristics of the regulatortubes.

ln accordance with my invention the indi-- In the present instance'asindicated on the schematic diagram the line voltage may fluctuatebetween 400 to 750 volts. The normal voltage of the circuitisapproximately 600 volts. Lamp 1 operates on 64 volts. It is necessaryto have in series with the lamp a dissipating voltage of approximately536 Volts.

The carrying capacity of a single voltage regulator tube isapproximately 2 amperes. By connecting a plurality-of these tubes inparallela regulator circuit of any desired carrying capacity may beobtained. For the service contemplated at the present the total maximumamperage that may be present in the circuit is approximately 12 amperes.The average current isapproximately 3 to 5 amperes.

There is liable to be at any moment surges of current greatly in excessof this amount of current. In the event of lamp burnout the regulatortubes must be capable of carrying constantly for prolonged periods oftime approximately 12 ainperes of current. I therefore prefer to connectin the parallel circuit a total of 12 voltage regulator tubes, adjustingeach tube to carry a maximum of 1 ampere at normal operating voltage.This provides a 100 per cent margin of safety and in the event of lampfailure the entire load of the circuit may be carried indefinitely bythe tubes without injury thereto.

Having broadly `and specifically outlined the nature of my invention itis apparent that there are many variations and departures that may bemade from the specific embodiment thereof without essentially departinglfrom the nature thereof, and such variations and departures are`anticipated which fall within the scope of the following v claims:

What is claimed is: 1. In an electrical system comprising a vafrombecoming oversaid variable resistance, said resistance being connectedat one end to ground potential and at the other end to a source ofpositive potential less than the starting potential of said gasdischarge tube.

2. In an electrical system comprising a variable source of highpotential, a dissipating resistance to obtain a current of lowerpotential, an electrical device operating at this lower potential and aplurality of gas discharge devices for maintaining said lower potentialconstant, of means for regulating the individual current carryingcapacities of said gas discharge devices comprising a variableresistanceconnected electrically in series with each of said gas discharge tubesto a mid tap connection of said variable resistance, one end of each ofsaid resistances being grounded and the other end of each of which areconnected in parallel to a source of positive potential less than theoperating potential of said gas discharge device. v

3. In an electrical circuit comprising a variable source of highelectrical potential, a

tive side of the said electrical circuit and the other terminal toasource of positive potential on the negative side of the said electricaldevice.

5. In amelectrical circuit comprising a variable source of highelectrical potential, dissipating resistance means for reducing saidpotential to a lower potential, an electrical device operating at thislower potential, and a plurality of gas discharge regulator tubes formaintaining a constant lower potential for said electrical device, ofmeans for equally distributingthe electrical load of the circuit amongsaid gas discharge regulator tubes comprising a plurality of variableresistances having a center tap connection, means for electricallyconnecting the cathode electrode of each of said regulator tubes to oneof said center tap connections, means for electrically dissipatingresistance means for obtaining a current of lower potential, anelectrical deviceoperating'at this lower potential and voltageregulating means to maintain said lower potential substantiallyconstant, comprising a gas discharge voltage regulator tube, the meansfor regulating the current consuming properties of said gas dischargetube comprising a variable resistance having a center tap memberelectrically connected to the cathode electrode of the gas dischargetube, one of the terminals of said resistance being connected to groundpotential, the other terminal being electrically connected to a sourceof positive potential lower than the operating voltage of said gasdischarge device. 4

4. In an electrical circuit comprising a variable source of highelectrical potential, dissipating resistance means to obtain a currentof lower potential, an electrical device operating atthis lowerpotential, and voltage regulating meansin parallel to said electricaldevice comprising a gas discharge tube for maintaining said lowerpotential constant, the means for regulating the current consumingproperties of saidgas discharge tube comprising a variable dissipatingresistance p0- tentiometer in series therewith and electricallyconnected thereto from a center tap connection to one of the electrodesof said gas discharge tube, one'of the terminals of said potentiometerbeing connected to the nega-

